--TEST--
Yielding the result of a non-ref function call throw a notice
--FILE--
<?php
function foo() {
    return "bar";
}
function &gen() {
    yield foo();
}
$gen = gen();
var_dump($gen->current());
?>
--EXPECTF--
Notice: Only variable references should be yielded by reference in %s on line %d at pos %d
string(3) "bar"